Automatic work loader for vertical hobbing machine



May 12, 1959 O. E. STAPLES AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE Filed July 9, 1954 I v has |lh i INVENTOR. 077557741155 O. E. STAPLES May 12, 1959 2,885,929

AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE Filed July 9, 1954 8 Sheets-Sheet 2 INVENTOR. 0 f. Sin/ 455 I Byz j Arr-021w: vs

May 12, 1959 O- E- STAPLES 2,885,929

AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE Filed July 9. 1954 8 Sheets-Sheet 3 IN VEN TOR. 0775 674F455 HIT/23H? Y5 May 12, 1959 0. E. STAPLES 2,885,929

AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE I Filed July 9, 1954 8 Sheets-Sheet 4 INVENTOR. 077$ -7AAL5 May 12, 1959 STAPLES 2,885,929

AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE Filed July 9, 1954 v 8 Sheets-Sheet 5 U i J IN V EN TOR. 0275 Sma 55 BY M Q3 May 12, 1959 o. E. STAPLES 2,885,929

AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE Filed July 9, 1954 8 Sheets-Sheet 6 I ArrEA/EYS May 12, 1959 O. E. STAPLES AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE Filed July 9, 1954 8 Sheets-Sheet '7 INVENTOR.

Arr-o NEYS y 12, 1959 o. E. STAPLES AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE Filed Jul 9, 1954 8 Sheets-Sheet 8 INVENTOR. 0775 E. STAPLES AUTOMATIC WORK LOADER FOR VERTICAL HOBBING MACHINE Otis E. Staples, Cleveland, Ohio, assignor, by mesne assignments, to Textron, Inc., a corporation of Rhode Island y Application July 9, 1954, Serial No. 442,313 12 Claims. (Cl. 90-4) The present invention relates to a machine tool and, more particularly, to a machine tool, especially a hobbing machine, for performing an operation on a gear blank or similar workpiece.

An important object of the present invention is the provision of a new and improved machine tool, particularly a hobbing machine, for performing a grinding, cutting or similar operation on an annular workpiece such as a gear blank in which the workpieces are automatically moved from a storage place into position to be operated upon by the machine, the operation of the machine performed, and the finished workpieces ejected from the machine.-

Another object of the present invention is the provision of a new and improved machine tool, particularly a hobbing machine, for performing a cutting or similar operation on an annular workpiece, such as a gear blank, and including arbor means to be received by workpiece for supporting the workpiece during the operation, the machine being so constructed and arranged that the blanks may be both automatically placed on the arbor means and removed therefrom upon the completion of the operation performed by the machine.

Another object of the present invention is the provision of a new and improved machine tool, particularly a hobbing machine, for performing a grinding, cutting or similar operation on a gear blank or similar workpiece and having arbor means adapted to be insertedinto the workpiece for holding the workpiece during the operation performed by the machine, and power actuating means for positioning the workpiece and for inserting the arbor into the workpiece.

Another object of the present .invention is the provision of a new and improved machine tool, particularly a hobbing machine, for performing a cutting, grinding, or similar operation on a gear blank or similar workpiece, and having arbor means to be pressed through the workpiece for supporting the workpiece during the operation performed by the machine, a spring-loaded tail center adapted to engage the outer end of the arbor means, backing means intermediate the arbor and the tail center and engageable with the workpiece to be operated upon and the tail center to-buck the workpiece while the arbor is pressed therethrough, hydraulic means for moving the arbor from an inactive position to press it through a workpiece and into engagement with the tail center and for holding the arbor into engagement with the tail center during the operation performed by the machine, the machine being so constructed and arranged that the pressure may be relieved after the insertion of the arbor into the workpiece and priorto the "ice performing of the operation to facilitate the removal of the backing means from intermediate the blank'and the tail center.

Another object of the present invention is the provision of'a new and improved hobbing machine for performing a grinding, cutting, or similar operation on a gear blank or similar workpiece, and having a workhead including a rotatable work spindle, an axially movable work supporting arbor coaxial with the Work spindle and. rotatable therewith, and power means to axially move the arbor and hold the arbor in an outward position during the hobbing operation.

The invention resides in certain constructions and combinations and elements of parts, and further objects and advantages will be apparent to those skilled in the art to which it relates from the following description of the preferred embodiment described with reference to the accompanying drawings forming a part of this specification, in which:

Fig. 1 is a perspective view of a hobbing machine embodying the present invention; 7 I

Fig. 2 is a fragmentary elevational view of the machine of Fig. 1 showing the turret magazine for storing gear blanks;

Fig. 3 is a plan view of the portion of the machine shown in Fig. 2;

Fig. 4 is a fragmentary elevational view, with portions cutaway, showing the mechanism for automatically posi tioning and supporting a gear blank in position to be hobbed;

Fig. 5 is a sectional view taken approximately along line 55 of Fig. 4; f

Fig. 6 is a plan view of the magazine turret mechanism detached from the machine;

Fig. 7 is a diagrammatic view of the hydraulic'mechanism of the machine;

Figs. 8 and 8a are diagrammatic electrical circuit diagrams of the control circuit for the machine illustrated;

Fig. 9 is a fragmentary elevational view showing the relative positions of the ejecting mechanism and of the loading mechanism while the arbor is being' pressed through a gear blank to be bobbed; and

Fig. 10 is a fragmentary plan view looking from approximately line 1-0-10 of Fig. 9 in the direction of the arrows.

The present invention is suitable for use in machine tools where it is desired to perform a cutting, grinding, or similar operation upon a gear blank or'similar workpiece. The invention is particularly suitable for use in hobbing machines and, for purposes of illustration, has been embodied in a vertical hobbing machine of the type illustrated and described in US. Patent 2,537,967 to T. F. Carlin, issued January '16; 1951 and the patents referred to therein, the construction and operation of which will not be described in detail except where necessary for an understanding of the construction and operation of the present invention. Sufiice it to say that the machine is of vertical construction and comprises a base A, a vertical column or gooseneck B supported on the base A, a workhead C vertically movable upon spaced pairs of ways 10, 11 on the column B, and a tool or hob 7 head D carried by a cylindrical member slidably supported in a horizontal cylindrical aperture in the column B and adjustable therein toward and away from the workhead.

The work W, in this case a gear blank, is adapted to Patented May 12, .1959.

be rotatably supported in the workhead C by an arbor 12' attached to the upper end of a work spindle 13. The outer end of the arbor 12 is adapted to engage a springloaded tail center 14 supported by means mounted on vertical ways 15 formed on the workhead. A hob or tool spindle is rotatably supported in the hob head D and during operation of the machine is rotated in timed relation to the rotation of the work spindle 13 by a cut motor 16, shown in the circuit diagram for the machine, located in the lower part of column B and operatively connected to the respective spindles in a manner similar tothat disclosed in the aforesaid patent.

The workhead C is adapted to be vertically reciprocated along the spaced pairs of ways 10, 11 to cause the gear blank W carried by the arbor 12 to be moved axially past a hob or other tool 19 aflixed to the hob spindle and to return the workhead to its initial position by means of a cooperating lead screw and nut connected to the workhead 0 and the base A, respectively. The lead screw is located within a chip guard 20 and is driven at a relatively slow speed in timed relation to the rotation of the hob and work spindles from the work spindle drive. The nut is rotatably supported in a housing 21 bolted to the base A and is adapted to be rotated at a relatively high speed through the medium of a self-locking worm and worm wheel by a high speed, reversible rapid'trave-rse motor 22 shown in the circuit diagram, located within the column B and connected to the Worm by a shaft 23.

According to the present invention, the gear blanks W are positioned on the arbor 12 and removed therefrom by power actuated means. The gear blanks W to be operated upon are stored in a turret mechanism 24 mounted on the ways 15 of the workhead C and comprising a plurality of circularly spaced magazines 25. The gear blanks W move from the magazines 25 into a drop chute 26, as is best shown in Fig. 4, to a loading mechanism 27 for receiving the gear blanks at the end of the drop chute 26 and locating the gear blanks so as to be in position to be engaged by the arbor 12. Upon completion of the machining operation, the arbor 12 is removed from the workpiece and the workpiece ejected from the machine by ejector mechanism 28.

The magazines 25 of the turret mechanism 24 are rotatably and detachably supported on a base member 29 which is dapted to be secured to the Ways 15 of the workhead C. The upper portion of the base member 29 is provided with a circular wear plate 30 on which an index detent plate 31, to which the magazines are adapted to be fastened, rotates. Suitable antifriction bearing means 31a is provided intermediate the index detent plate 31 and the base member 29.

The magazines 25 are recessed in an indexing plate 32 and extend vertically therefrom. The indexing plate has an intercepter plate 33 secured to the underside thereof by a pin 34 which permits relative rotation between the index plate and the intercepter plate and prevents separation of the plates. The magazines 25 and the plates 32, 33 are adapted to be detachably supported on the index detent plate 31. Relative rotation between the intercepter plate 33 and the index detent plate 31 is prevented by a pin 35 adapted to be received in a recess in the underside of the intercepter plate 33. The pin 35 assures proper positioning of the magazines 25 and the index plate 32 with respect to the base member 29 of the turret mechanism, as well as preventing rotation as above stated.

Relative rotation between the indexing plate 32 and the intercepter plate 33 is adapted to be prevented by a spring-biased plunger 36 supported in the intercepter plate 33 and biased inwardly with respect thereto and having a head portion 37 adapted to be received in either one of two cut-out portions 38, 38a in the periphery of the indexing plate 32.

The indexing plate 32, the intercepter plate 33, and the index detent plate 31 are provided with a plurality of bores 39 aligned with the tubular magazines 25 supported by the indexing plate 32 The bores 39 through the intercepter plate 33 are aligned with the magazines 25 and the bores 39 of the indexing plate 32 and the index detent plate 31 when the head portion of the plunger 36 is received in the cut-out portion 38. When the plunger 36 is pulled outwardly and the intercepter plate 33 and indexing plate 32 are relatively rotated to engage the head portion 37 of the plunger 36 in the cut-out portion 38a of the indexing plate 32, the bores 39 of the plate 33 are moved out of alignment with their corresponding bores 39 in the plate 32 preventing the passage of gear blanks from the lower ends of the magazines 25. The rotatable part of the turret mechanism 24 is indexed to bring the bores 39 successively into alignment with the drop chute 26 which extends vertically through the base member 29. The indexing detent plate 31 is provided with a plurality of spring-biased detents 40 adapted to be received in recesses in the wear plate 39 to properly align the tubes 39 and the drop chute 26 each time the magazines are indexed.

The above structure makes it possible to,load a unit comprising the magazines 25, the indexing plate 32, and the intercepter plate 33, with the unit removed from the machine and to then properly position the unit on the machine. The intercepter plate may be rotated to a position which blocks the passage of gear blanks from the magazines 25 to facilitate the loading operation.

In the illustrated embodiment, the tube immediately above the plunger 36 is blocked and not used in the illus trated embodiment. However, it may be desirable to provide a turret mechanism without the intercepter plate 33 and in such a construction the tube would not be blocked due to the absence of the plunger 36.

The indexing movement of the turret 24 to bring the magazines 25 into alignment with the drop chute 26 is accomplished by means of a hydraulic cylinder 41 having a piston rod 42 extending outwardly therefrom and supporting at its outer end a block 43 having a dog 44 pivoted thereto. The dog 44 is spring-biased against a stop by means of a spring 45 to maintain it in the position shown in Fig. 3. In this position, the dog 44 extends outwardly of the block 43 and is adapted to engage one of a plurality of vertical indexing studs 46 extending upwardly from the plate 32 adjacent each magazine 25 with one magazine having a vertical indexing rod 46a rather than a stud, the rod 46a extending the height of the magazine adjacent the plunger 36. The outward movement of the piston rod 42, when pressure is applied to the proper side of the piston of hydraulic cylinder 41, causes the turret 24 to rotate to bring the next magazine 25 into alignment with the drop chute 26. When the piston is returned to its normal position, the spring 45 permits the dog 44 to ride over the adjacent stud 46.

The hydraulic cylinder 41 is controlled by means of a limit switch 47 supported from the workhead C in a position adjacent the upper end of drop chute 26. The limit switch 47 has a spring-biased arm 48 adapted to extend into the drop chute 26 and including a roller mounted on its outer end adapted to engage the gear blanks at the upper end of the drop chute 26. The arm is springbiased and is held in one position against the bias of the spring by engagement with the gear blanks in the drop chute. When the particular magazine above the drop chute 26 has been emptied, the arm will lose engagement with the gear blanks W, causing the actuation of the hydraulic cylinder 41 to index the turret 24.

The lowest gear blank W in the drop chute 26 rests on a horizontal surface 50 of a block-like loading member 51 of the loading mechanism 27. The loading member 51 is adapted to receive a blank from the drop chute 26 and is supported for horizontal movement on a support plate 52. The support plate 52 extends to a point above the work spindle 13 and is provided with an aperture 53 in its left-hand end as it is viewed in Fig. 5 to permit the passage theret hrough "of the arbor '12. A stripping block 54 is mounted on the left-hand endof the support plate 52 and is likewise provided with an aperture 55 to pass the arbor 12. i

The movement of the loading member 51 along the support plate 52 is guided by a slot 56 and actuated by means of a hydraulic cylinder 57 having its piston rod connected to the loading member 51. A gear blank W in position on the loading member 51 is adapted to be held in proper position by spring fingers 60, 61 supported on opposite sides of the loading member 51 and adapted to engage the outer periphery of the gear blank. The fingers 60, 61 are secured to the loading arm 51 by means of a bolt 62 passing through the spring fingers and the loading member and having springs for biasing the fingers located intermediate the outer ends of the bolt and the fingers 60, 61. The fingers 60, 61 have their inner sides tapered so that when the loading member 51 is in the retracted position shown in Fig. 5, the righthand ends of the fingers may be moved inwardly toward the loading member 51 to spread the left-hand ends thereof. In order to open the fingers 60, 61 as the loading arm moves into position to receive a gear blank W from the drop chute 26, spaced vertical studs 63, 64 are mounted on the plate 52 adjacent the drop chute 26 and are adapted to engage the fingers 60, 61 and move their right ends inwardly to spread the left ends of the fingers. In order to prevent the next gear blank from dropping from the drop chute 26 when the loading member is moved from under the drop chute to position. the gear blank on the member over the arbor 12, a horizontal plate 65 is fixed to the top of the loading member and extends rearwardly therefrom. As the loading member 51 moves to the left, the next gear blank in the drop chute engages the top of the horizontal plate 65 and is held in the drop chute until the loading member 51 is returned and in position to receive the blank.

The arbor 12 is reciprocable between a retracted and extended position by means of a hydraulic cylinder 66 supported from the underside of workhead C. A rod 67 extends upwardly from the piston of hydraulic cylinder 66 coaxially with the Work spindle 13 and threads into the lower end of arbor 12, as best shown in Fig. 4. The arbor 12 is keyed for axial movement within a hollow cone-like support member 68 having a flanged base 69 adapted to be connected to the top of work spindle 13 and rotated therewith.

, The hydraulic cylinder 66 may be actuated. to withdraw the arbor 12 to a retracted position and permit the locating of a gear blank W by the loading member 51 in a position adjacent the outer end of the arbor 12 and coaxially therewith. After the gear blank .W hasbeen positioned coaxially with the retracted arbor 12, an anvil block 70 is movedrto position a portion 70a thereof intermediate the gear blank W and the tail center 14 by means of a hydraulic cylinder 71 also actuated for ejecting a completed workpiece from the machine, as will be described in detail hereinafter. The anvil block 7041 is provided with an opening 72 to permit the passage of the arbor 12 therethrough and is positioned to engage the upper surface of the gear blank W and the lower end of a cylinder 73 for supporting the tail center 14. The cylinder 73 is secured to the base member 32 and comprises a lower chamber for supporting the piston-like tail center 14 and an upper chamber in which a compression spring 74 is located and adapted to apply a downward force to the tail center 14 through bearing means 75,- the bearing means 75 permitting relative rotation between the spring 74 and the tail center 14. The upper end of the cylinder 73 is closed by means of a threaded plug 76 which provides a means for adjusting the compressive force of spring 74.

The underside of the anvil block 70 is cut away, as indicated in the drawings, to form a shoulder 77 adapted to engage a finger 78 supported by the loading arm 51. The

hydraulic 71 and the anvil block are supported by a bracket 79 fixed to or forming a part of the stripping block 54, or the support plate 52, and the bracket 79 has a slot 80 therein adapted to receive and guide the finger 78. When the loading arm 51 is in position where the gear blank thereon is coaxial with thearbor 12, the finger 78 is located within the slot 80 and extends upwardly therefrom to be engaged by the shoulder 77 on the anvil block 70 to limit the movement of the anvil block to a point where the opening 72 is aligned with the arbor 12. Upon completion of the hobbing operation, the hydraulic cylinder 66 is actuated to move the arbor 12 to a retracted position, the movement of the arbor causing the ger blank W supported thereon to be stripped off the arbor by the stripping block 54. The hydraulic cylinder 71 is then actuated to move the anvil block toward the work, and since the loading arm is in a retracted po: sition, the movement of the anvil block is not stopped by the finger 78 and the block moves a suflicient distance to enable the shoulder 77 to engage the gear blank W, now on top of the stripping block 54, and eject the gear blank into a hopper chute 81 which leads the blank from the work spindle to a box or bin 82 located at the base of the hobbing machine. The movement of the anvil is guided by a key 85 fixed to the anvil.

A hydraulic system for operating various hydraulic components of the illustrative machine is shown schematically in Fig. 7. Referring to Fig. 7, the hydraulic system comprises a duplex pump having pump cylinders 101, 102 and driven by an electric motor 103. The discharge from the pump cylinder 101 is directed into a pipe line 104 for supplying fluid pressure to the hydraulic cylinder 57 for actuating the loading member 51, the hydraulic cylinder 41 for indexing the turret mechanism, and hydraulic cylinder 71 for operating the ejector mechanism 28. The pressure in line 104 is reduced, in the illustrated embodiment to approximately 100 pounds, by a pressure-reducing valve 105 having its outlet connected to a pipe line 106. An accumulator 107 is also connected to the pipe line 106 to provide a stored fluid pressure supply for the rapid movements of the hydraulic cylinders permitting a smaller volume pump to-be used than would be possible without the use of an accumulator.

The hydraulic cylinder 57 for the loading member 51 is connected to the line 106 by means of a solenoid valve 108 which is movable to two positions. The valve 108 is spring-biased to one of its positions and is moved by the energization of a solenoid 110 to its other position. In its spring-biased position, fluid pressure is applied to the side of the piston of cylinder 57 for moving the load ing member 51 to its retracted position and the other 7 side of the piston is connected to drain; and when the valve 108 is in its second position, pressure is applied to the side of the piston for moving the loading member into position above the arbor 12, and the other side of the piston is connected to drain.

The solenoid valves 111, 112, spring-biased to one position and moved by solenoids 113, 114, respectively, to a second position, are provided for connecting the hydraulic indexing cylinder 41 and the hydraulic cylinder 71 of the ejecting mechanism to the line 106. The valves 111, 112 are like the valve 108 in construction and connection so that the pistons of the hydraulic cylinders 41, 71 are in their retracted position when the solenoids 113, 114 are deenergized and are moved to their other position to perform their operation when the solenoids 113, 114 are energized.

The discharge of the pump cylinder 102 is connected to a pipe line 116 for supplying fluid pressure to a hydraulic cylinder 117 for moving the hob head D toward, and away from, the work W. The cylinder 117 is connected to line 116 by means of a solenoid valve 118 which is like solenoid valve 108. When the valve 118 is in its spring-biased position, pressure is applied to the side ofthe piston of hydraulic cylinder 117 for moving the hob head away from the work and the other side of the piston connected to drain, but when a solenoid 120 for moving the valve 118 to its second position is energized, pressure is applied to the side of the piston for moving the hob head D toward the work and connecting the other side of the piston to drain.

The line 116 is also connected to the inlet side of a constant pressure reducing valve 121 having its discharge connected to the chuck hydraulic cylinder 66 through solenoid valve 122 and 123. The valve 122 has two positions and is moved to one position by the energization of a solenoid 124a and to its other position by the energization of solenoid 124b. The valve 123 is springbiased to one position and moved to its other position by the energization of a solenoid 125. When the valve 123 is deenergized and solenoid 124b is energized, the outlet of reducing valve 121 is connected to the side of the piston of hydraulic cylinder 66 for moving the arbor 12 to its retracted position through valve 122, the valve 123 being bypassed by a pipe line 126 connected directly from the valve 122 to the hydraulic cylinder 66. When the solenoid 124:: is energized, fluid pressure is connected by the valve 122 to a line 123 connected between the valve 122 and the valve 123, through the valve 123, and from the valve 123 to a line 130 between the valve and the side of the hydraulic cylinder for moving the piston thereof in a direction to move the arbor 12 outwardly of the work spindle 13 into engagement with tail center 14.

After the arbor 12 has been pressed through the gear blank W, and prior to the removal of the anvil block 70 from intermediate the blank and the tail center, it is desirable to release the pressure forcing the arbor 12 into engagement with the tail center 14. This is done by energizing solenoid 125 of solenoid valve 123 to the valve to its second position and connect the line 130 to drain through the valve 123. The line 126 to the other side of the piston is still connected to drain in this condition since the solenoid 124a of valve 122 remains energized. An accumulator 131, similar to accumulator 107, i

is preferably connected to the outlet of the reducing valve 121.

The pressure in the line 116 is controlled by a springloaded bypass valve 133, connected in parallel between the line 116 and drain with a combined solenoid valve 134 and spring pressure relief valve. When the solenoid 134a, shown in the circuit diagram, for operating valve 134 is energized, fluid flow is blocked through the valve, and the relief setting of bypass valve 133, preferably 500 pounds, controls the pressure in line 116. When the valve 134 is deenergized, flow is vented through the valve at a pressure, in the illustrated embodiment, of approximately 40 pounds per square inch. The energization of solenoid 134a is controlled by a hydraulic pressure switch 135 connected in series with the solenoid 134a. The contacts of the switch 135 are normally closed but are opened when the pressure in line 116 reaches the desired maximum pressure, in the illustrated embodiment, 500 pounds per square inch to deenergize the solenoid and vent the line pressure at a lower pressure. When the line pressure drops to a lower pressure, say 480 pounds per square inch, the contacts of switch 135 reclose to again energize the solenoid 134a to move the valve to its blocking position. This arrangement will decrease work losses in the system, as well as be understood by those skilled in the art.

The limits of movements of the loading mechanism, the ejector mechanism, the automatic cycle of the machine, and the indexing mechanism for the turret 24 are controlled by limit switches adapted to be actuated by the various members and components of the machine. As hereinbefore stated, the indexing of the turret 24 is under control of the limit switch 47 adapted to engage the gear blanks within the drop chute 26. The forward movement of the ejector mechanism 28 to position the anvil block 70 in bucking position is controlled by a limit switch 136, mounted underneath the support plate 52 by a bracket 137 connected to the support plate. The limit switch is actuated by a dog 138 fixed to the underside of the loading member 51 underneath the support plate 52.

During the cutting operation, the travel of the workhead C is controlled by a travel cycle control limit switch 140 mounted at the top of column B and adapted to be actuated by a dog 141 carried by the portion of the workhead C adapted to slide on the vertical ways 10 on the upper portion of the column B. A rapid traverse to cut switch 142 is mounted below the limit switch 140 and adapted to be actuated by spaced dogs 143, 144 on the upper portion of the workhead to change the movement of the workhead to rapid traverse to a feed movement.

The tool spindle of the hob head D is of the type which moves axially during the cutting operation to spread the wear of the hob over all of the teeth of the hob. A hob shift microswitch 145, shown in the circuit diagram, is provided to terminate operation of the machine when the spindle has shifted the hob through its entire length. A limit switch 146 is also actuated by the hob head D when the hob head is moved to its retracted position away from the work W.

A plurality of selector switches are mounted on the column B for selecting the particular manner in which it is desired to operate the machine. A selector switch 147 having Manual and Automatic positions is provided for selectively operating the machine automatically or with the components under the control of the operator. A selector switch 148, having an 011 position, an Automatic position, and a Manual position, is provided for manually or automatically causing the hob head to remain in engagement with the work W until the hob is finished rotating upon completion of the cutting operation. A selector switch 150, having an Off position, an Automatic position and a Manual position, is provided to enable the ejecting and bucking to be done under the control of the operator, or to be done automatically with the machine on its automatic cycle. Selector switches 151, 152, 153 are provided for controlling the loading mechanism 27, the outward movement of the arbor 12, and the return of the arbor 12. The selector switches 151, 152, 153 are similar to the selector switch 150 and provide for the same selective operations of the components under the control of the switch as the selective switch 150 of the ejector mechanism. A job selector switch 154 is provided for enabling the workhead to be selectively fed upwardly or downwardly during the cut operation, and a selector switch 156 is provided for determining the direction of rotation of the cut motor.

Figs. 8 and 811 show schematically the portion of the electrical circuit for controlling the machine illustrated which is necessary for an understanding of the present invention. The details of the circuit of the machine which are not necessary for an understanding of the present invention and are not shown herein, are fully set forth in the above-referred to patents and are well known to those skilled in the art.

When it is desired to operate the illustrated machine automatically, the selector switches 147, 148, 150, 151, 152 and 153 are moved from their Ofr position to their Automatic position. The selector switch 154 is moved to determine the direction of feed of the workhead C and it will be assumed in the description that the work head starts in its lower position and is moved upwardly during the cut stroke. The selector switch 156 is moved from its Oif position to select the direction of rotation of the cut motor.

Immediately upon moving the selector switch 147 to its automatic position, a circuit is completed for energizing an automatic recycle timer relay 162. The circuit for energizing automatic recycle timer 162 includes wire 163 connecter to L1, normally closed contacts 164 of work head overtravel limit switch 165, wire 166, normally closed contacts of stop push button switch 167, Wire 168, wire 169, switch arm 170 of selector switch 148 now in automatic position, automatic contact 171 of selector switch 148, wire 172, wire 173, normally closed contacts 174 of hob shift microswitch 145, wire 175, wire 176, normally closed contacts 177 of automatic load time delay relay 178, wire 179, normally closed contacts 180 of recycle interrupt relay 181, wire 182, normally closed contacts 183 of hob slide return limit switch 146, wire 184, normally closed back contacts 185 of travel cycle control limit switch 142, wire 186, up contact 188 of automatic-manual selector switch 154, switch arm 189 of selector switch 154, wire 190, relay coil of automatic recycle timer relay 162, and wire 192 to L2. The energization of relay 162 closes its normally open contacts 191 to start the automatic cycle.

After positioning the selector switches, a start push button switch 193, having a set of normally open contacts 194 and a set of normally closed back contacts 195, is depressed to start the operation of the machine. The depression of the push button switch 193 closes the normally open contacts 194 and completes circuits to holding relay 196, holding relay 197, automatic load time delay relay 178 and automatic holding relay 198 through the job selector switch 154 for determining an upward or downward movement of the workhead. The selector switch 154 comprises a plurality of switch arms which are movable from an Oif position into engagement with one contact when the selector switch is moved to its Up position, and a down contact when the selector switch is moved to its Down position. The circuit to relay holding 196, completed upon depression, comprises wire 163 connected to L1, normally closed contacts 164 of the overtravel limit switch 165, wire 166, the normally closed contacts of stop push button switch 167,.wire 168, now closed contacts 194 of push button switch 193, wire 205, switch arm 206 and up contact 207 of selector switch 154, wire 208, normally closed back contacts 209 of travel cycle control limit switch 142, wire 210, switch arm 211 and up contact 212 of selector switch 154, wire 213, the relay coil of holding relay 196, and wire 214 to L2.

The wire 213 is also connected to the relay coil of holding relay 197 as well as to the relay coil of holding relay 196 and, therefore, the holding relay 197' is energized to close its normally open contacts 215 and open its normally closed contacts 216 simultaneously with the energization of holding relay 196. The energization of holding relay 196 closes its normally open contacts 217, i

218, 219 and 220.

Automatic load delay relay 178 is also energized upon a depression of the start push button 193. The purpose of the automatic load delay relay 178 is to introduce a time delay in the movement of the loading member 51 to its loading position. The circuit for energizing the automatic load delay relay 178 comprises wire 163 connected to L1, normally closed contacts 164 of overtravel limit switch 165, wire 166, normally closed contacts of stop push button switch 167, wire 168, now closed contacts of start push button switch 193, wire 205, automatic contact 222 and switch arm 223 of selector switch 147, wire 224, relay coil of automatic load time delay relay 178, and wire 225 to L2.

The above-described circuits have energized the holdingrelays 197, 196, the automatic load time delay relay 178, and the automatic recycle timer relay 162. Upon energization of these relays, a circuit is completed to the solenoid 110 of solenoid valve 108 for controlling the movement of the piston of loading mechanism hydraulic cylinder 57. The circuit for energizing the solenoid 110 comprises wire 226 connected to wire 224 which is' connected to L1 in the manner described with reference to energization of-automatic load time delay relay 178, now closed contacts 191 of automatic recycle timer relay 162, wire 227, wire 228, now closed normally open contacts 229 of automatic load time delay relay 178, wire 230, now' closed contacts 219 of holding relay 196, wire 231, normally closed contacts 232 of a loading member return time delay relay 233, wire 234, automatic contact 235 of load selector switch 151, switch arm 236 of selector switch 151, wire 237 and solenoid of solenoid valve 108, and wire 238 to L2. Upon energization of solenoid 110, the loading member 51 moves to a position above the retracted arbor 12.

The closing of the contacts 191 of automatic recycle timer relay 162 in addition to setting up the circuit to solenoid 110 also causes the energization of automatic holding relay 198 completing a holding circuit about the contacts 191 so that the automatic cycle will repeat itself. The circuit for energizing automatic holding relay 198 includes wire 241 connected to wire 227, which is, in turn, connected to L1 in the manner set forth in describing the energization of solenoid 110 and wire 242 connecting the automatic holding relay 198 to L2. The holding circuit completed from L1 upon the energization of automatic holding relay 198, includes wire 163 connected to L1, normally closed contacts 164 of limit switch 165, wire 166, normally closed contacts of stop push button switch 167, wire 168, wire 169, switch arm and automatic contact 171 of load selector switch 148, wire 172, wire 173, normally closed contacts of hob shift microswitch 145, wire 175, wire 176, wire 244, now closed contacts 245 of automatic holding relay 198, wire 246, switch arm 247 and automatic contact 248 of selector switch 147, and wire 249 connected to Wire 227 completing the holding circuit from L1 about the contacts 191 of automatic recycle timer relay 162.

The closing of contact 229 of automatic load delay relay 178 to complete the circuit to the solenoid 110 of the loading mechanism, also completes a circuit to the recycle interrupt relay 181 to open its normally closed contacts and 250 and to close its normally open contacts 251. The opening of contacts 250 breaks a circuit for energizing solenoid 114 to retract the anvil block 170 upon actuation of loading member 51. The opening of contacts 180 breaks the circuit to the automatic recycle timer relay 162, opening its contacts 191 in the circuit to the solenoid 110 of the loading mechanism. The opening of contacts 191 does not have any effect electrically in view of the holding circuit completed about contacts 191 by the energization of automatic holding relay 198 and described in detail above. The circuit for energizing the recycle interrupt relay 181 includes wire 253 connected to wire 230 which is connected to L1 in the manner described above through the holding circuit set up by the energization of automatic holding relay 198 and through the contacts 229 of automatic load delay relay 178, wire 254, the coil of recycle interrupt relay 181, and wire 255 to L2.

I The movement of the loading member 51 to its position wherein a gear blank thereon is positioned over the arbor 12, actuates limit switch 136 for controlling the movement of the ejector mechanism and arbor 12. The closing of limit switch 136 completes a circuit from L1 through the contacts 245 of automatic holding relay 198,

the now closed contacts of automatic load delay relay 178, 229 and wire 253, in the manner above described, the circuit from wire 253 including wire 257, now closed contacts of limit switch 136, wire 258, wire 259, the now closed contacts 218 of energized holding relay 196, wire 260, the solenoid of an arbor delay relay 261, and wire 262 to L2.

The energization of arbor delay timer 261 closes its normally open contacts 263 to complete a circuit from L1 to energize an arbor solenoid relay 264, a hob start timer relay 265 and the loading mechanism return delay relay 233.- Upon the closing of contacts 263 of arbor delay timer 261, a circuit is completed from L1 through the holding circuit completed by automatic holding relay 198, as above described, now closed contacts 229 of automatic load delay relay 178, wire 230, wire 280, now closed contacts 263 of arbor delay timer 261, wire 281, wire 282 connected to the solenoids of arbor solenoid relay 264, hob start timer relay 265 and loading mechanism return delay relay 233, and from the solenoids of the respective relays to L2.

The closing of limit switch 136 .by the loading member 51 also causes the energization of solenoid 114 of solenoid valve 112 for actuating the hydraulic cylinder 71 to move the anvil block 70 into a position above the gear blank now positioned above the arbor 12 by the loading member 51. The circuit for energizing the solenoid 114 upon the closing of the limit switch 136 is the same through the limit switch 136 as the circuit described for energizing arbor timer delay relay 261. From the limit switch 136, the circuit for energizing solenoid 114 includes wire 258, auotomatic contact button 266 and switch am 267 of ejector mechanism selector switch 150, wire 268, solenoid 114 of solenoid valve 112 and wire 269 to L2. The anvil block 70 is actuated to its bucking position immediately upon the closing of limit switch 136 and the energization of the solenoid 114. The movement of the arbor 12 from its retracted position, however, is delayed after the position of the anvil block 70 due to the time delay in the closing of contacts 263 of arbor delay timer 261.

Upon the closing of contacts 263 of arbor delay timer 261 and the consequent energization of the arbor solenoid relay 264 to close its normally open contacts, 283, 284, and 285, the arbor solenoid 124a is energized to move the solenoid valve 122 to its position for supplying pressure to cylinder 66 to move the arbor 12 through a gear blank positioned on the loading member 51 and into engagement with the tail center 14. i

The circuit for energizing the solenoid 124a from L1 comprises wire 163, normally closed contacts 164 of travel limit switch 165, wire 166, normally closed contacts of stop push button 167, wire 168, wire 169, switch arm 170 and automatic contact 171 of selector switch 148, wire 172, now closed contacts 273 of arbor solenoid relay 264, wire 286, automatic contact 287 and switch arm 288 of arbor On selector switch 153, wire 289, solenoid 124a and wire 290 to L2.

After the arbor 12 has been pressed through the gear blank supported by the loading member 51, the loading mechanism return delay relay 233, which was energized simultaneously with arbor solenoid relay 264, operates to close its normally open contacts 291 to complete a circuit to energize the solenoid 125 of solenoid valve 123 for releasing the pressure applied to the arbor 12 upon the energization of solenoid 124a. The release of the pressure on the arbor 12 permits easy withdrawal of the anvil block 70. The circuit for energizing solenoid 125 of pressure release solenoid valve 123 is completed through the now closed contacts 263 of the arbor delay timer 261 in the manner set forth in describing the energization of the arbor solenoid relay 264. The circuit from the contacts 263 for energizing the pressure release solenoid 125 includes wire 282 connected to one contact of the contacts 263 through wire 281, wire 293, now closed contacts 291 of load arm mechanism return delay timer 233, wire 294, normally closed contacts 295 of hob start timer relay 265, wire 296, solenoid 125 of pressure release solenoid valve 123 and wire 297 to L2. It Will be noted from the above circuit that the operation of hob start timer relay 265 must be delayed a longer period of time than the delay in the operation of the loading mechanism return delay timer 233 to return the loading mechanism since the circuit for energizing solenoid 125 includes the normally open contacts of relay 233 and the normally closed contacts 295 of hob start timer relay 265.

The operation of loading mechanism return delay relay 233 opens its normally closed contacts 232 breaking the circuit to the solenoid of solenoid valve 108 causing the solenoid valve to move to a position for returning the loading member 51 to its retracted position under the drop chute 26. The return of the loading member 51 opens the limit switch 136 causing the deenergization of solenoid 114 to return the anvil block 70 and the deenergization of arbor delay relay 261 to open its normally open contacts 263 breaking the circuit through the contacts 245 of automatic holding relay 198 and the contacts 229 of the automatic load delay relay 178 to the arbor solenoid relay 264, hob start timer relay 265 and the loading mechanism return delay relay 233. These latter relays, however, are maintained in an energized condition by a holding circuit completed upon the energization of arbor solenoid relay 264. This holding circuit is completed from L1 to the wire 176 through the selector switch 148 and hob shift microswitch in the manner set forth in the description of the holding circuit completed by the energization of automatic holding relay 198. The circuit from wire 196, completed by the energization of arbor solenoid relay 264, includes wire 299, now closed contacts 217 of holding relay 196, wire 300, now closed contacts 284 of arbor solenoid relay 264, wire 301 and wire 282 to the coils of relays 264, 265 and 233.

Upon the operation of hob start timer 265, circuits are completed for starting the hobbing operation and the circuit to the solenoid 125 of the pressure release solenoid valve 123 is broken, causing full pressure to be applied to the arbor 12 to again press the arbor 12 into engagement with the tail center 14. The circuit to the solenoid 125 is broken by the opening of normally closed contacts 295 of relay 265. The closing of normally open contacts 302 of hob start timer relay 265 completes circuits to start the operation of the cut motor 16 through the holding circuit, just described, comprising the contacts 217 of holding relay 198 and contacts 284 of arbor solenoid relay 264. The circuit from the now closed contacts 284 of arbor solenoid relay 264 includes wire 301, now closed contacts 283 of arbor solenoid relay 264, wire 303, now closed contact 302 of hob start timer relay 265, wire 304, now closed contacts 220 of holding relay 196, wire 305, normally closed contacts of ejector mechanism return limit switch 306, wire 307, back contacts of start push button switch 193, wire 308, wire 309, back contacts 310 of rapid traverse to feed limit switch 140, wire 311, normally closed contacts 312 of hob slide return relay 313, wire 314, the coil of a cut motor relay 315 having normally open contacts 316, 317, 318, and wire 319 to L2. The energization of the solenoid of the cut motor relay 315 closes its normally open contacts 316, 317, 318 to complete circuits from L1, L2 and L3 to the cut motor 16 through the selector switch 156. The selector switch 156 has two switch arms 320, 321 connected to the contacts 316, 318, respectively, each arm being engageable with one of two contacts to determine the direction of rotation of cut motor 16. The contacts 317 are connected directly to the cut motor 16. The ejector mechanism return switch 306 is supported on the bracket 78 of the ejector mechanism and prevents operation of the cut motor unless the ejector mechanism has returned. It is often desirable to cause the first portion of the workhead movement to be at a rapid traverse rate rather than at a cut rate. Switch and circuit means for accomplishing this is provided and is described hereinafter.

Simultaneously, with the energization of the cut motor relay 315, a holding relay 322, having normally open contacts 323, 324 and normally closed contacts 325, 326, is energized to close its normally open contacts. The relay 322 is connected in parallel with the normally closed contacts 312 of the hob slide return relay 313 and the coil of cut motor relay 315 by a wire connected to wire 311, normally closed contacts 328 of a hob slide return delay relay 329, wire 330, the coil of cut motor holding relay 322 and wire 331 to L2. The energization of cut motor 'relay 32 2 completes a holding circuit for the cut motor relay315 which is independent of the arbor solenoidrelay 264, the-holding relay 196 and the hob start timer'relay 265, 'andwhich comprises wire 163 connected to L1, normally closed contacts of overtravel limit switch 165, stop push button switch 167, wires 168, 169, switch arm 170 and automatic contact 171 of selector switch 148, wire 332, now closed contacts 324 of cut motor holdingrelay 322, wire 333,wire 309, contacts 310 of rapid traverse to cut limit switch 140 and from the switch 140 to the coils of the cut motor relay 315 and the cut motor holding relay 322 in the manner above described. Solenoid 1200f solenoid valve 118, for controlling the application of fluid pressure to the hydraulic cylinder 117 for moving the hob head outwardly into work-engaging position, is also connected in parallel with the normally closed contacts 312 of hob slide return relay 313 and the cut motor relay 315 by wire 334 connected to wire 311, automaticconta ct 335and switch arm 336 of selector switch 148, wire 337, solenoid 120 of solenoid valve 118 and wire 338 to L2. The hob is therefore moved outwardly toward the work simultaneously with the energization of the cut motorl- With the start of the -cut motor 16 and the outward movement of the hob'head D, the electrical circuit remains in the conditionwhich it is in at the time the cut morons started until theworkhead has moved the gear blank' W past the hobga'nd the cut stroke of the machine completed. It has been assumed that the cut stroke of the machine is accomplished with the workhead moving in an upwardly direction. Upon the completion of the cut stroke,the travel cycle limit switch 142 is actuated to open its contacts 185, 209and close its contacts 340, 341. The opening of contacts 185 and 209 deenergizes holding relay-196'ancl holding relay 197, which, inturn, causes the deenergization of automatic loadidelay relay 178,"which has been maintained in an energized position afterthe opening of contact 191 of automatic recycle timer delay l62 by a holding circuit completed by contacts 215 of holding 'relay 197. One side of the contacts 215 is connected to L1 through the hob shift microswitch 145, switch arm 170 of selector switch 148, stop push button167 and overtravel limit switch 164 by wire 343, the other side of 'the'contactsbeing connected, by wire 424, to wire 205, which is, in turn, connected to the coil of relay 178 through selector switch 147 and wire 224. It is tobe noted thatthe' cut motor is not stopped by the deenergizationof relays 196, 197 and 178 because of the holding circuit completed by the contacts of cut motor holding relay 322.

The closing of the normally closed contacts 216 of holding relay-197*upon the deenergization thereof completes a circuit-to energize the hob slide return relay 313. This circuit is completed 'from L1 through the overtravel switch 165, normallyclosed stop push button 167, switch arm 170 of selector switch 148, wire 332, wire 344, now closed contacts-216 of deenergized holding relay 197, wire-345, wire 346, now.closed contacts 323 of energized relay 322, wire 347, wire 348, the normally closed contacts 349 of hob slide deenergizing relay 350, wire 351, the coil of hob slide return relay 313. and wire 352 to L2. The coil of-hob'slide return delayrelay 329 is connected in parallel {with the solenoid of hob slide return relay 313, having one side connected to wire 351, and the other side 'connectedto L2 by wire 353. Upon "theenergization ofhob slide return relay 313, its normally open contacts 312 in the circuit to the cut motor relay'315 areopened, deenergizing the relay. The cut motor holding relay 322, 'however, remains energized, keeping its contacts 324 closed to maintain the solenoid 120 of solenoid-valve 118 for controlling hob slide hydraulic cylinder 117 energized. A predetermined time "after the energization of hob slide return .delayrelay 329, the. relayop'erates to open'its normally closed contacts 328 and the circuit of the solenoid cut motor relay 322,

14 causing the opening of; contacts 324 and the deenergization ofsolenoid of solenoid valve 118. Upon the deenergization of solenoid 120, the hydraulic cylinder 117 is actuated to move the hob head inwardly to its return position.

The deenergization of cut motor relay 322 also opens its contacts 323 in the circuit for energizing the hob slide return delay relay 329 and closes its contacts 325 in the circuit for energizing the hob slide deenergizing relay 350. The circuit to the 'hob slide return delay relay 329 is maintained upon a deenergization of cut motor holding relay 322 by normally open contacts 354 of now energized hob slide return relay 313, which are connected in parallel with the contacts 323 of cut .motor holding relay 322 by wire 355 connected to wire 345 and wire 356 connected to wire 348.

The circuit for energizing the hob slide deenergizing delay relay 350, upon the deenergization of cut motor holding relay 322 from L1, includes the overtravel limit switch 165, the stop push button switch 167, the switch arm of selector arm 148, wires 332, 344, now closed contacts 216 of holding relay 197, wire 345, wire 355, now closed contacts 354 of hob slide return relay 313, wire 356, normally closed contacts 325 of cut motor holding relay'3'22, wire 357, the coil of hob slide deenergizing delay relay 350 and wire 358 to L2. Upon the energization of hob slide deenergizing delay relay 350 its normally closed contacts 349, in the circuit for energizing the hob slide return delay relay 329 and the hob slide return relay 313, are opened, deenergizing the relays.

The return of the hob head to its retracted position closes the contacts of hob slide return limit switch 146. The closing of the limit switch 146 completes a circuit to energize a-rapid traverse down relay 360 to return the workhead to its lower position, The circuit for energizing the relay 360 from L1 includes overtravel limit switch 165, stop push button switch 167, switch arm 170 of selector switch 148, wire 172, wire 173, hob shift microswitch 145, wire 175, wire 176, normally closed contacts 177 of now deenergized automatic load delay relay 165, normally closed contacts 180 of recycle interrupt relay 181, now closed contacts of hob slide return limit switch 146,wire 184, wire 361, normally closed contacts 326 -of now deenergized cut motor holding relay 322, wire 362, switch arm 363 and up contact 364 of job selector switch 154, wire 3 65, now closed contacts 340 of travel cycle control limit switch 142, wire 366, switch arm 367 and up contact 368 of job selector switch 154, wire 369, the coil of rapid traverse down relay 360, and wire 370 to L2. The energization of rapid traverse down relay completes circuits to L1, L2, L3 to the rapid traverse motor 22 to move the workhead rapidly to its lower position. While moving to its lower position, the work- 'head actuates rapid traverse cut switch to move it from the position shown in the circuit diagram to its second position, opening its contacts 310 and closing its contacts 371.

Simultaneously with the energization of the rapid traverse down relay, the solenoid 124k for actuating solenoid valve 122 to its position -for supplying fiuid pressure to the arbor hydraulic cylinder 66, to move the arbor to its retracted position, is energized. The circuit for energizing the solenoid 12412 from L1 is the same as that for energizing rapid traverse down relay from L1 through the hob slide return limit switch 146 to wire 184. The circuit from the wire 184 includes automatic contact 372 of arbor 01f selector switch 152, switch arm 373 of selector switch 152, wire 374, switch arm 375 and contact 3760f arbor on selector on switch 153, wire 377, solenoid 124b of solenoid valve 122 and wire 378 to L2. The energization of the solenoid 124b, and the return of the arbor 12 to its retracted position, strips the hobbed gear blank from the arbor 12 on the stripping block 54. It maybe seen that if the selector switches 283, 289 are moved'to their manual positions, the automatic circuits to the solenoid 1241; will be broken. When the workhead C is returned to its lower position, the rapid traverse motor is stopped by the actuation of travel cycle control limit switch 142 to its position shown in the circuit diagram. This opens its contacts 340 in the circuit for energizing rapid traverse down relay 360, deenergizing the relay.

The closing of hob slide return limit switch 146 also completes a circuit for energizing solenoid 114 of solenoid valve 112 for controlling the operation of the ejecting mechanism hydraulic cylinder 71 to move the piston of the cylinder outwardly to eject the hobbed gear blank. This circuit from L1 through the hob slide return limit switch 146 is the same as that for energizing the rapid traverse down relay 360 and the solenoid 12411 of the solenoid valve 122 for controlling the arbor hydraulic cylinder '66. From the hob slide return limit switch 146, the circuit for energizing solenoid 114 includes wire 184, now closed contacts 185 of travel cycle control limit switch 142, wire 186, up contact 188 and switch arm 189 of job selector switch 154, wire 190, wire 380, now closed contacts 381 of automatic holding relay 198, wire 382, normally closed contacts 250 of recycle interrupt relay 181, wire 383, wire 258, automatic contact 266 and switch arm 267 of ejector mechanism selector switch 150, wire 268, solenoid 114 of solenoid valve 112 for controlling the actuation of ejector mechanism hydraulic mechanism 71, and wire 269 to L2.

The actuation of travel cycle control limit switch 142 also completes a circuit for energizing the automatic recycle timer relay 162 in the manner described above. It will be noted that the automatic holding relay 198 has remained energized throughout the operation of the machine because of the holding circuit completed by its normally open contacts 245. Therefore, upon energization of the automatic recycle timer relay 162 and the consequent closing of its contacts 191, L1 is applied to the switch arm 206 of job selector switch 154 causing the machine to start its repeat cycle. In the repeat cycle, the recycle interrupt relay 181 will be energized simultaneously with the solenoid 110 of solenoid valve 108 for controlling the operation of the loading mechanism hydraulic cylinder 57, breaking the circuit to solenoid 114 and causing the ejecting mechanism to retract as the loading member 51 is moved forward due to the energization of solenoid 110.

While the description of the circuit was started with rapid traverse to cut limit switch 140 in the position shown in the circuit diagram, it will be noted that the limit switch will normally be in a position wherein the contacts 310 are open and the contacts 370 closed before the workhead starts its upward cut stroke. In this position, upon the operation of hob start delay relay 265 to close its normally open contacts 302 and start the cut motor, in the manner above described, the position of the limit switch 140 will first cause the energization of a rapid traverse up relay 384 to cause the workhead C to start its upward movement at a rapid traverse rate. The circuit for energizing the rapid traverse up relay is the same from L1 through the back contacts 195 of the start push button switch 193 as that described for energizing the cut motor relay 3 15 upon the closing of contacts 302 of the hob start delay relay 265. From the back contacts 195 of the start push button switch 193, the circuit for energizing rapid traverse up relay 384 includes wire 308, wire 309, now closed contacts 371 of switch 140, wire 385, switch arm 386 and up contact 387 of job selector switch 154, wire 388, the coil of rapid traverse up relay 384, and wire 389 to L2. As the workhead moves upwardly at a rapid traverse rate, the limit switch 140 will be actuated to open its contacts 371 and close its contacts 310 to change the movement of the workhead from a rapid traverse rate to a cut rate.

If it is desired to move the workhead downwardly during the cut stroke, rather than upwardly, as just described,

the job selector switch 154 is moved to its down position causing the switch arms 206, 211, 367, 363, 386 and 189 of the switch to engage their respective down contacts 391, 392, 393, 394, 395, 396. When in this position, the energization of the automatic recycle timer relay 162 is no different than its operation when the switch arm 189 of selector switch 154 is in its up position since the up contact 188 and the down contact 369 are both connected to wire 184 by either the contacts 185 of travel cycle control limit switch 182 or the contacts 341, regardless of the position of the travel cycle control limit switch. The switch arm 189 also controls the energization of solenoid 114 of the ejector mechanism to cause the ejector mechanism to eject the hobbed gear blank and, therefore, the action of the ejector mechanism will be also unafiected by the change of the switch arm 189 from its contact with contact 188 to engagement with contact 396.

When the cut stroke is to be accomplished with the workhead working down, the limit switch 142 will be in the position it occupies with the workhead in its up position at the beginning of each cycle. In this position, the contacts 341 and 340 are closed, while the contacts 185 and 209 of the switch are open. When the switch arms of the selector switch 154 move to their down position, the holding relays 196, 197 are energized upon depression of the push button 193 to close contacts 194 by a circuit from L2, which includes switch arm 206 of selector switch 154, down contact 391 of selector switch 154 now engaged by theswitch arm 206, wire 365, now closed contacts 340 of travel cycle limit switch 142, wire 366, switch arm 367 and down contact 393 of job selector switch 154, and wire 398 to wire 213 connected to the coils of relays 196 and 197. It may now be seen that the selector switch enables the holding relays for the automatic cycle to be energized when the switch is moved for causing the workhead to move downwardly during the cutting operation.

The shift of the travel cycle control limit switch 142 to its down position also changes the connection of contacts 371 from the circuit of the rapid traverse up relays 384 and connects them into the circuit of the rapid traverse down relay 360 so that when the limit switch is actuated during the return of the workhead, after completion of the cut stroke, the workhead will rapid traverse in a down direction until the time limit switch 140 is again actuated to change the operation from rapid traverse to cut. The switch arm 386 determines whether or not the rapid traverse up or rapid traverse down relay is energized by the closing of contacts 371 of the rapid traverse to cut limit switch 140. When the switch arm 386 is in engagement with the down contact 395, the circuits made by the closing of the contacts 371 includes Wire 3855, switch arm 386, down contacts 395 of selector switch 154, wire 399 to wire 369, which is connected to the rapid traverse down relay 360.

The movement of the switch arm 363 of the job selector switch 154, when in engagement with its down contact 394, changes the circuit so that when the hob slide return switch 146 is closed, the rapid traverse up relay 384 is energized to return the workhead upon completion of the work stroke. The circuit from the switch arm 363 includes the down contact 394, wire 400, wire 208, contacts 209 of travel cycle limit switch 142, wire 210, switch arm 211 and down contact 392 of the job selector switch 154, wire 401 and wire 388 to rapid traverse up relay 384.

During the portion of the cycle that the recycle interrupt relay 181 is energized, a circuit is conditioned from L1 by the closing of normally open contacts 409 of the recycle interrupt relay 181. These are connected in series with the normally open limit switch 47 and the solenoid 113 of solenoid valve 111 for controlling the indexing hydraulic cylinder 41. During the time that the contacts 409 are closed, it the magazine above the drop 'locate a full magazine over the drop chute 26.

The motor 103- for supplying fluid pressure to the hydrauliccylinders of the machine is energized by depressing a push' but'ton switch'402 connected across L1 and L2 in series with a stop push button switch 403 having normally closedcontactsand, the. solenoid of a motor contactor "40 4. Energization of the motor contactor 404 closesits-normallyopen contacts 405, 406, 407 to apply L1, L2 and L3 to the motor 103, and close its normally open contacts 408 to complete a holding circuit around the start push button switch"402. I

" When it is desired to'p'erform the various operations manually, the selector switch 147 is moved to the manual position, andtheselector switches 148, 150, 151, 152 and 153 are moved from their neutral positions to their manual positions at.thetime that the operation is to be performedf When theYselector switch 147 is moved to its manual position, the loading member 51 may be moved inwa rdl y by moving selector switch 151 to the manual 3 position. This'cornpletes a circuit from L1 to L2, includingovertravel limitswitchl165, stop push button switch 11167,wire 410,,fmanual"contact 411 and switch arm 412 of selector switch 147, wire 413, wire 414, manual contact415iand switch am 236. of loading'mechanism selector switch 151,wire 237,fisolenoid 110 of solenoid valve 0,8, iwire 238 to L 2;

"' he movement of sw' ch 'ar' 412 of selector switch 147 into engagement with the manual control contact 411, also conditions thelcircuitfor manually controlling the ener-' gization of solenoid114 of solenoidvalve 112 of the ejecting mechanism, a fcircuit for manually controlling the solenoid valveZ 125 for releasing the arbor pressure, anda circuit for the'solenoid valve 122 for controlling the "pressure applied'jto thearbor cylinder 66. When the ejector fmechanism' fselectorswitch, is moved to manual,

.thesolenoid 114'of'the solenoid valve 112 is connected to the .switch arm 412by wire'413, wire 416, manual .conta'ct417 and arm 261 of ejector mechanism selector. switch 150, and wire 268 to solenoid114, This causes thejejector mechanism to moveoutwardly.

Thejsolenoid 124aof the solenoid valve 122 may be energized by moving 'thesolenoid on selec tor switch 153 to its manual positioncompleting a circuit from Ll through the switch'farm 412 of selector switch 147 andjwire 413 in the manner described above .toth'e solenoid 124a. The circuitfrom wire 413 comprises manual contact-.420, of selector switchj153, switchv ,arni'288 of selector switch 153, wire289, solenoid 124a, and wire 292m L2 1* Acir cuit maybe ma lally lcompleted for energizing solenoid 125 of -a'i 'bor pressure release valve 123 by depressing a push buttqn switch 421 havi ng one side connected to the wire 413, and the other sideto the sole- ;noid 125, the other. side ot-the solenoid 125 being con c e f q L l y.vv ev i. a

EWhen iti is desired to energize the .solenoid l24b to retract the arbor 12, the arbor off selector switch 152 is moved to itsmanual position which moves the arm 373 into engagement with a manual contact 422 connected to -the wire-413 which is, in turn, connected to L1 in the manner described. above. The switch arm 373 is connected to the solenoid 124b andthen toL2 by w1re374 connectedto switcher-m, 37 3, switch arm 375 of arbor on ;se lector;switch 153 ,fautomatic contact376 of arbor on selector switch153, and wire 377 connected to the solenoid ,12 4b. It ,will; Lbe noted that to energize the solenoid 124b, the arbor on selector switch 153 must be moved .to its automatic position. Moving the arbor on selector switch153. to its: automatic position, assures that the :solenoid 124a; cannot the; energized simultaneously with -the solenoid "124b..=.:Since-theselector switch147. is in matic cycle. The closing of the contacts 215 of the holding relay 197 completes a circuit through the automaticmanual selector switch 147 to the cut motor 16 or to the rapid traverse motor 22, depending upon the position of rapid traverse to cut switch 140. If the switch is in the position shown in the circuit diagram, the circuit will be completed to the cut motor relay 315 from L1 and includes wire 163 connected to L1, overtravel limit switch 165, stop push button switch 167, Wire 168, now closed contacts 194 of start push button switch 193, wire 205, wire 424, now closed contacts 215 of holding relay 197, wire 343, wire 175, normally closed contacts of hob shift microswitch 145, wire 173, wire 172, switch arm 425 of selector switch 147, manual contact 426 of selector switch 147, wire 308 to the rapid traverse to cut limit switch 140. The circuit for energizing either the rapid'traverse or the cut motor, depending upon the position of rapid traverse to cut limit switch 140 from the switch 140, is the same as in the automatic cycle and will not be described again.

It will be seen from the above description that the present machine is capable of being operated to auto matically perform a hobbing operation .on blanks held by the turret mechanism 24. The sequence of operations including the transferring of the blanks from the storage or turret mechanism 24, the impaling .of a blank on the arbor 12, the actuation of the cut and feed motors to perform the operation on the blank, and the ejecting of the blank from the machine is completely automatic and does not require the intervention of an operator. The circuit, however, is also set up so that the various operations may be performed under the manual control of the operator to facilitate setting up the machine in the first instance.

a While a preferred form of the invention has been described in considerable detail, it will be apparent that the invention is not limited to the constructions shown or the particular operations referred to and it is my intention to cover hereby all adaptations, modifications, and changes which come within the practice of those skilled in the art to which the invention relates and the scope of the appended claims.

Having thus described my invention, I claim:

1. In a machine tool for operating on an annular workpiece, a frame; tool supporting means mounted on said frame; work supporting means including an arbor axially movable relative to said frame and adapted to be pressed into the opening in the annular workpiece for supporting the workpiece in fixed relationship to the arbor and in operative relation to a toolsupported by said tool supporting means; means supported by said frame for receiving a workpiece and moving the workpiece to a position adjacent to the end of and coaxial with said arbor; power actuated means for relatively moving said arbor and the workpiece in one direction to press the arbor into the opening of the workpiece and in the opposite direction to separate the arbor and workpiece upon completion of the operation on the workpiece and retractable anvil means supported on said frame and moved to engage said workpiece to buck the axial forces of said arbor means as the latter engages the workpiece and retractable to a position clear of the workpiece during the machining operation.

2. In a machine tool for operating on an annular workpiece, a frame; tool supporting means mounted on said frame; work supporting means including an arbor adapted to be received by the opening in the annular workpiece for supporting the workpiece in operative relation to a tool supportedby said tool supporting means; a tail center '19 axially spaced from said arbor means; means supported by said frame for receiving a workpiece and moving the workpiece to a position adjacent to the end of and coaxial with said arbor and intermediate said arbor and said tail center; power actuated means for moving said arbor in one direction to position the arbor in and coaxial with the workpiece and in the opposite direction to separate the arbor and workpiece upon completion of the operation; and power actuated retractable anvil means disposable between said workpiece and said tail center for bucking the force of said arbor when passing through said workpiece and operable to eject a completed workpiece from the machine, said anvil means being retracted to a position clear of the workpiece while the workpiece is being operated upon by the machine.

3. In a machine tool for operating on a workpiece having an opening therein; a frame; tool supporting means supported by said frame; a power actuated rotatable work spindle having a work supporting arbor rotatable therewith and extending axially therefrom, said arbor being movable axially of said work spindle and adapted to be pressed into the opening in the workpiece to mount the workpiece on the arbor for rotation therewith; power actuated means for moving said arbor axially outwardly of said spindle from a first position to a second position for supporting the workpiece in operative relation to said tool supporting means; power actuated means for receiving workpieces and moving the workpieces to a position adjacent the end of said arbor when said arbor is in its first position, the Workpiece being positioned by the last said means so that the opening therein is adapted to receive the arbor upon movement to its second position and the movement of said arbor from its second position to its first position withdrawing the arbor from the opening in the workpiece, and power actuated retractable anvil means operable to dispose the anvil means in engagement with a workpiece positioned to receive said arbor to buck the forces due to the arbor as the arbor is pressed into the workpiece and retractable to a position clear of said workpiece while the latter is being operated uponby the machine tool.

4. In a machine tool for operating on a workpiece having an opening therein; a frame; tool supporting means supported by said frame; a rotatable work spindle having a work supporting arbor rotatable therewith and extending axially therefrom, said arbor being movable axially on said Work spindle and adapted to be received by the opening in the workpiece; power actuated means for moving said arbor axially outwardly of said spindle from a first position to a second position for supporting the workpiece in operative relation to said tool supporting means; means for receiving workpieces and for moving the workpieces to a position adjacent the end of said arbor when said arbor is in its first position, the Workpiece being positioned by the last said means so that the opening therein is adapted to receive the arbor upon movement to its second position and the movement of said arbor from its second position to its first position withdrawing the arbor from the opening in the workpiece; a tail center engageable by said arbor when the latter is in its said second position, and retractable anvil means disposable between said tail center and a workpiece in position to be engaged by said arbor to buck the workpiece when the arbor passes therethrough and movable from said position to a position clear of the workpiece while the operation is performed on the workpiece.

5. In a machine tool for operating upon a workpiece having an opening therethrough, means for delivering workpieces to a discharge point, axially movable arbor means adapted to be received in the opening of the workpiece to support the workpieces against movement relative to the arbor means during the machine operation, loading means for delivering a workpiece from said discharge point and positioning it for engagement with said arbor 20 means, power actuated means for pressing said arbor means through and for removing said arbor means from the opening in a positioned workpiece, power actuated retractable anvil means engageable with the workpiece for bucking the axial forces of said arbor means as the latter is positioned in the workpiece, and means for operating said power actuated anvil means in timed relationship to said loading means and to said power actuated means for operating the arbor means.

6. In a machine tool for operating upon a workpiece having an opening therein, arbor means adapted to be recevied in the opening of the workpiece to support the workpieces against rotation with respect to the arbor means during the machine operation, loading means for delivering a workpiece and positioning it in a position for engagement with said arbor means, power actuated means for moving said arbor means into and out of engagement with the workpiece, and means responsive to the positioning of a workpiece by said loading means for actuating said arbor means into engagement with the workpiece, means responsive to the completion of the machine operation on the workpiece for moving said arbor means out of engagement with the workpiece, and power actuated retractable anvil means engageable with a workpiece in position to be engaged by said arbor means for bucking the workpiece when the arbor means moves into engagement therewith and retractable to a position clear of said workpiece during the machine operation and operable in timed relation to said loading means and said means for moving said arbor means out of engagement with the workpiece to buck the workpiece.

7. In a machine tool for operating upon a workpiece having an opening therethrough, storage means for storing nad delivering the workpieces to a discharge point, axially movable arbor means adapted to be pressed through the opening of the workpiece to support the workpiece in fixed relationship to the arbor means during the machine operation, power actuated loading means for receiving a workpiece at said discharge point and positioning it in a position for engagement with said arbor means, power actuated means for moving said arbor means into and out of engagement with the workpiece, means responsive to the positioning of a workpiece by said loading means for actuating said arbor means into engagement with the workpiece, means responsive to the completion of the machine operation on the workpiece for moving said arbor means out of engagement with the workpiece, power actuated retractable anvil means operable in timed relation to said loading means and said means for moving said arbor means into and out of engagement with the workpiece to engage and buck the workpiece against the axial forces of said arbor means during the'eng'aging movement of said arbor means, and means for effecting the retraction of said power actuated anvil means when said arbor is engaged with said workpiece.

8. In a machine tool for performing an operation on a gear blank, a frame, a rotatable tool spindle supported by said frame, a rotatable work spindle, means for producing relative movement between said work spindle and said tool spindle along the axis of said work spindle, an axially movable arbor within and coaxial said work spindle and rotatable therewith, said arbor extending outwardly of said spindle and adapted to be pressed through the axial opening of a gear blank to support the gear blank in position to be operated upon by a tool supported by said tool spindle, a spring-loaded tail center adapted to engage the outer end of said arbor and cooperate therewith, fluid pressure responsive means for axially moving said arbor from a retracted position out of engagement with said tail center into an operating position in engagement with said tail center, storage means for storing a plurality of gear blanks and delivering them to a-discharge point, a first movable member having a first position to receive a and said tail center with the blank coaxialwith said arbor, fluid pressure responsive means for actuating said member between its positions, a second movable member having an opening therethrough for passing said arbor supported by said.frameflforwmovingiinfia first direction from an inactive position. to a second position intermediate said blank and said-tail center with the axis of the arbor, fluid pressurerresponsivemeans for moving said second member in its .s aid first direction and in a return direction opposite to said first direction, stop means on said first movable member engageable by said second'movable member when the first movable member is in its second position to limit movement of said second movable member in its said first direction and correctly position said second movable member in its said second position, said second movable member including means for ejecting a blank from the machine upon movement of said second movable member in said first direction past its said second position when said arbor is in a retracted position and said first movable member is in its said first position, and control means for controlling the operations of said fluid pressure responsive means to sequentially position a blank coaxially with said arbor, move said second member to its active position, press said arbor through said blank into engagement with said tail center, move said second movable member to its inactive position and said first movable member to its first position, and to retract said arbor upon completion of the machine operation on the blank.

9. In a hobbing machine for performing an operatio on a workpiece, a frame, a rotatable tool spindle supported by said frame, a workhead including a rotatable work spindle, power actuated means for producing rela-' tive movement in either of two opposite directions between said Work spindle and said tool spindle along the axis of said work spindle at a first rate and at a second rate higher than said first rate, said spindle including :an arbor rotatable therewith, adapted to be moved from a retracted position into engagement with a workpiece to support the workpiece in position to be operated upon by a tool supported by said tool spindle, fluid pressure responsive means for axially moving said arbor fiom its retracted position to an operating position in engagement with a workpiece, storage means for storing a plurality of workpieces and delivering them to a discharge point, a movable member on said workhead having a first position to receive a workpiece at the discharge point and movable to transfer workpiece from said discharge point to a position to be engaged by said arbor when moved to its operative position, fluid pressure responsive means for actuating said movable member, and control means for controlling the operation of said power actuated means and said fluid pressure responsive means to sequentially move said movable member to deliver a blank from said storage means into a position to be engaged by said arbor, actuate said arbor into engagement with the positioned workpiece, produce said relative movement in one direction between said spindles to relatively move the workpiece by a tool supported by said tool spindle at the first rate of movement, and upon completion of the operation of the workpiece relatively move said spindles in the opposite direction :at said second rate and retract said arbor from engagement with the workpiece.

10. In a hobbing machine for performing an operation on a workpiece having an opening therethrough, a frame, a rotatable tool spindle supported by said frame, a work head including a rotatable work spindle, power actuated means for rotating said spindles, power actuated means for producing relative movement between said work 22 spindle and -'-said tool spindle' either directiorr along the axisof-said work spindle at a first rate and*'-'at""a second r'atehigher than the first rate, an axially movable *arbor within and coaxial with said 'work 'spindleand rotatable therewith, said arbor extending outwardlyof said spindle and adapted to be pressed through the opening of a'workpiece to support"theworkpiece'in position to be operated upon by a tool 'supportedjby said tool spindle, a spring-loaded tail center adapted to engage the outer end of said arbor and cooperate therewith, power actuated means for axially moving said arbor from a retracted position out of engagement with said tail center toan operating position into engagement with said tail center, storage means for storing a plurality of gear blanks and delivering them to a discharge point, a first movable member having a first position to receive a gear blank at the discharge point and movable to transfer blanks from said discharge point to a position intermediate the said arbor in its retracted position and said tail center with the opening in the workpiece coaxial with said arbor, power actuated means for moving said member between its positions, a second movable member having an opening therethrough and supported by said frame for movement in a first direction from a second position to an active position intermediate a positioned workpiece and said tail center with the opening therethrough aligned with the axis of the arbor and in position to allow the arbor to pass therethrough, stop means on said first movable member engageable by said second movable member when said first movable member is in its said second position to limit the movement of the second movable member in said first direction and correctly position said second movable member in its said second position, said second movable member being movable in its said first direction from its said first position for ejecting a blank from the machine when said arbor is in a retracted position and said first movable member is in its said first position.

11. In a machine tool, an axially movable arbor to be pressed into an opening in a workpiece, loading means for supporting a workpiece in the path of said arbor with an opening therein positioned to receive said arbor, an anvil member having a first position clear of said workpiece and said path and movable across said path 5 to a second position, power actuated means for moving said member between its said positions, said member having a portion adapted to engage and eject a workpiece in said position when moved from its said first position to its said second position, means engageable with said anvil member for terminating the movement of said member short of said second position and to position said member in a third position, said member having a portion in said third position disposed adjacent the path of said arbor and adapted to engage a workpiece supported by said loading means in the path of said arbor to buck the workpiece as the arbor passes therethrough, and means for effecting movement of said member to its said third position to buck a workpiece prior to themachining operation and to said second position to eject a completed workpiece.

12. In a machine tool, an axially movable arbor to be pressed into an opening in a workpiece, loading means for supporting a workpiece in the path of said arbor with an opening therein positioned to receive said arbor, an anvil member having a first position clear of said workpiece and said path and movable across said path to a second position, power actuated means for moving said member between its said positions, said member having a portion adapted to engage and eject a workpiece in said position when moved from its said first position to its said second position, means engageable with said anvil member for terminating the movement of said member short of said second position and to position said member in a third position, said '23 member having aportion in said third :position disposed adjacent the'pathof said'arbor and adapted to engage a workpieee supported by said loading means in the path of said arbor-to buck the workpiece as the arbor passes therethrough, and meansfor effecting movement of said member to its said third position to buck a workpiece prior to the machining operation and to said second position to eject a completed workpiece in timed relationship to the operation of the arbor and load means.

References Cited in the file of this patent UNITED STATES PATENTS 379,307 Codling Mar. 13, 1888 Moncrieff I an. 22, 

